The old man put his oars (船桨)in the water and _______ the smooth surface of the lake.
He _______ his gun under the tree where he was __________.
_______he has got a chance, he might as well make full use of it.
That art center is _______ used to be a factory, ______ millions of tractors were produced.
It is ________ Beth to drink so much; I wonder if she is all right.
There is no light in the room. They must have gone to the lecture.__________?